When specifying a remote location with SSH (which require -e ssh, otherwise it uses rsync own protocol and requires rsync server/daemon to be started on the other end), you have to write it following this pattern :

[user@]short_name[.domain]:[path]

If you ommit user@ it willl assume the remote user is the same that the one used on the local machine
If you ommit .domain it will use your domain search settings (like any other name resolution)
If you omit path it will use the remote user's home directory (Note: it's the same as writing user@server:~ )

So here, you just have to replace the space by a colon : like Grumpy wrote it in his answer.